The predecessor instrument to the present invention is manufactured by Zellweger Uster, Inc. and is known as AFIS. This instrument separated fibers and neps into one airstream and trash into another airstream using the device disclosed in U.S. Pat. No. 4,512,060. Trash is defined as foreign matter having size greater than about 50 .mu.m. Sometimes this foreign matter is called dust and trash but we shall use the designation trash here for simplicity. In this predecessor, AFIS, it was necessary to test three sets of replicate samples of textile material separately to determine information about fibers, neps and trash. One test and one separate sample of textile material was necessary for each type of entity for each replicate. Although this AFIS provided the best data available at the time for automated and fast textile testing instruments, there was a need for better data and increased speed. An improved sensor was discovered and is disclosed in the application Ser. No. 07/493,961, and the instrument incorporating the improved sensor, also known as AFIS, is manufactured by Zellweger Uster, Inc. For clarity and consistency with the references, the first instrument is called AFIS-0 and the instrument with the improved sensor is called AFIS-1.
The present invention is a further improvement in AFIS-1 and is directed primarily to testing rate considerations. It was first discovered that the improved sensor of AFIS-1 produced data that would enable substantially simultaneous measurement of multiple data from the same sample of textile material. By substantially simultaneous it is meant that nep data, fiber data and trash data are obtained by testing a single sample of textile material and detecting and measuring substantially all of the neps and trash and detecting and measuring a representative sample of the fibers. Thus, this improvement eliminates the need to run three separate tests on typically 3-5 replicates of three separate samples to obtain data for neps, trash and fiber. Also, it was discovered that such data could be obtained using only one sensor, if desired. The testing speed improvements discussed above are made possible by a new analyzer circuit, which is a hybrid analog and digital circuit in the preferred embodiment. Speed of operation is increased by a factor of three in the present invention as compared to AFIS-1 or AFIS-0.
With the advent of high speed handling, the need for accurate and high speed characterization of entities in a test sample is necessary. Although the basic count and size information of trash and individual fibers is sometimes sufficient, more detailed information about neps and trash is required.
Neps in staple textiles are broadly defined to be small clumps or entanglements of fiber. They are one of the three main constituents of staple fiber. However, neps may be broken down into three further categories; mechanically generated neps, seed coat neps, and shiny (or immature) neps. A mechanically generated nep is created during the opening, ginning, and carding of the cotton and can range from 0.1 mm to 5 mm in diameter. They are tightly knotted cotton or man-made fibers consisting of a tangled core and a long fiber tail that cannot be opened during processing. Seed coat neps or seed coat fragments are composed of a collection of fibers that remain attached to the shell of the cotton seed. When viewed in visible light, they are small tufts of fibers attached to a dark central core. A shiny nep or dye resistant nep is a collection of very immature or dead cotton fibers. These are formed on the cotton seed when a part or all of the cotton seed undergoes stress that stops the maturation process of the fibers. The resulting fibers are very thin and weak with very little lateral stiffness and can easily form tight clumps of closely packed, parallel fibers. These very immature fibers cannot absorb dyestuffs properly and result in white specks and discolorations in finished fabric. These shiny neps may or may not be attached to the seed coat.
With these descriptions in mind, it is easy to understand the importance of classifying neps into these categories. Mechanically generated neps are indicative of the aggressiveness of the processing machinery and, therefore, an accurate count of these particles is used to fine tune or even overhaul processing machinery. The distinction between polyester, the most common man-made fiber, and cotton neps is important as they are often processed separately and combined in sliver form at a drawing frame.
Seed coat fragments originate from the cotton plant and their numbers are influenced by the method of ginning and cleaning and the species of cotton. Seed coat fragments are particularly troublesome in that they are a major source of yarn defects. The number of these particles per unit weight provide useful information to the grower about seed-to-fiber tenacity, to the ginner about the aggressiveness of the seed removal process and to the processor about the quality of the raw material.
Shiny nep counts predict the dyeability of the processed and spun cotton. Specifically, the number of these shiny neps per gram predicts the quality of the appearance of the finished and dyed fabric allowing the quality conscious mill operator to direct the highest quality material to the most demanding applications.
The quantity and quality of trash in a sample of fiber is important to textile processors for reasons analogous to those discussed above. Trash occurs in cotton primarily as a result of mechanical picking and such trash may be classified as fibrous or non-fibrous and may be further sub-classified as fibrous bark, fibrous grass or leaf, flake grass or leaf, thick trash (seed coat fragments and some bark), dust or fiber fragments. The classification of trash in a sample will reveal problems in prior processing, will facilitate corrective processing, and will help predict the quality of the end product (usually yarn) produced from the fiber.
Therefore, before any textile processor can significantly increase the efficiency or quality of their processing, much more detailed information about the raw materials, and particularly neps, is required. This need extends from the cotton grower and ginner up through the yarn or thread spinner and finally to the fabric mill.